Dutch great Ruud Gullit admits he's worried about Barcelona midfielder Frenkie de Jong.

The former Ajax star has suffered a sudden drop of form since the New Year and is being criticised in the local press.

Gullit revealed to Voetbal International: "I was worried about De Jong last year because I didn't think he was good enough.

"While all the media here in the Netherlands said he was so great. I didn't see it. You couldn't say that, because De Jong is the ideal son-in-law. But it's better to be critical of him. So that he himself knows that he must go a step higher.

"Two weeks ago, at the presentation of the Laureus Award, I was asked by Spanish journalists: 'What do you think of him?' They were not satisfied with him at all. The reporting in the Netherlands was not correct, so I am worried about that."